Vibrations: A momentum impulse starts a mass into oscillatory motion

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Homework Help Overview

The discussion revolves around a problem involving a mass attached to a spring, which is set into oscillatory motion by a sudden momentum impulse. Participants are exploring the implications of this impulse and its effect on the system's motion, as described in the context of vibrations and waves.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants are questioning the meaning of "sudden momentum impulse" and its role in initiating motion. There is discussion about the correct form of the equation of motion and the initial conditions for the system.

Discussion Status

Some participants have clarified the concept of the momentum impulse and its effect on the initial velocity of the mass. There is ongoing exploration of the relevant equations and initial conditions, with no explicit consensus reached on the final approach.

Contextual Notes

Participants are working from a specific problem statement in a textbook, which may impose certain assumptions about the system's behavior and the nature of the impulse applied.

Zamarripa
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Homework Statement
The system shown at rest in fig 1.1(a) could be set into vibration by giving the mass a sudden momentum impulse to the left:by trapping it with a hammer, for example. If the magnitude of the impulse is p1 and its given at time t=0, find (a) the amplitude and (b) the phase constant of the ensuing motion.
Relevant Equations
md^2x/dt^2-kx=0
The fig. 1.1(a) is a mass m attached to a spring that is fixed to a wall. I don't understand what does "a sudden momentum impulse" means. Is it an external force o what?
I imagined that the new equation of motion would be

md^2x/dt^2+dp1/dt-kx=0

md^2x/dt^2+mdv1/dt-kx=0

is this the equation i have to solve?

The problem is from the book Vibrations and Waves in physics from Ian Main.
 
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Zamarripa said:
don't understand what does "a sudden momentum impulse" means
It means going suddenly from rest to moving at some nonzero velocity.
 
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Zamarripa said:
Problem Statement: The system shown at rest in fig 1.1(a) could be set into vibration by giving the mass a sudden momentum impulse to the left:by trapping it with a hammer, for example. If the magnitude of the impulse is p1 and its given at time t=0, find (a) the amplitude and (b) the phase constant of the ensuing motion.
Relevant Equations: md^2x/dt^2-kx=0

The fig. 1.1(a) is a mass m attached to a spring that is fixed to a wall. I don't understand what does "a sudden momentum impulse" means. Is it an external force o what?
I imagined that the new equation of motion would be

md^2x/dt^2+dp1/dt-kx=0

md^2x/dt^2+mdv1/dt-kx=0

is this the equation i have to solve?

The problem is from the book Vibrations and Waves in physics from Ian Main.
The '"sudden momentum impulse" certainly means that the mass is given momentum by a sudden impulse p1 at t=0. Except for the initial moment, there is no external force.
What is the initial velocity of the vibration then?
Check the relevant equation, it is not correct.
 
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ehild said:
The '"sudden momentum impulse" certainly means that the mass is given momentum by a sudden impulse p1 at t=0. Except for the initial moment, there is no external force.
What is the initial velocity of the vibration then?
Check the relevant equation, it is not correct.
The initial velocity is v1=p1/m and the problem is just a simple harmonic oscillation with initial conditions x(t=0)=x0, v(t=0)=v1?
 
Zamarripa said:
The initial velocity is v1=p1/m and the problem is just a simple harmonic oscillation with initial conditions x(t=0)=x0, v(t=0)=v1?
Yes.
 
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